Minute and Large-Scale Synthesis of Covalent-Organic Frameworks in Water at Room Temperature by a Two-Step Dissolution-Precipitation Method

Low-cost, green, large-scale, room-temperature, and fastsynthesisof covalent organic frameworks (COFs) represents a highly desirableissue, due to both scientific and industrial interests, but remainsa big challenge. The disadvantage of the established solvothermalmethod for COFs is now seriously restricting their practical industrialapplications. We report herein aqueous synthesis of ketoenamine- andimine-linked COFs through a two-step dissolution-precipitation(DP) strategy. Impressively, using this DP method, we can preparefive ketoenamine-linked COFs and two imine-linked COFs in an idealsynthetic process with room temperature, 5 min reaction time, andlarge-scale products for one batch reaction, in the absence of aceticacid. These COFs show impressively high crystallinity and porosityand potential application in iodine and uranyl capture. This idealsynthetic route will pave a powerful methodology for making functionalCOFs with the value of practical industrial applications.